In transmission electron microscopy, the surface of a specimen is observed or analyzed by reflection electron microscopy or other method. When this reflection electron microscopy is utilized, the structure or topography of a specimen surface can be observed at a resolution of the order of 10 .ang.. However, it is impossible to know the chemical composition or chemical bonding energy of the specimen surface. Accordingly, when it is desired to know the chemical composition or chemical bonding energies in the specimen surface, photoelectron emission microscopy (PEEM) is a useful means, as described in "An Analytical Reflection and Emission UHV Surface Electron Microscope" by W. Telieps and E. Bauer, Ultramicroscopy, Vol. 17, pp. 57-66, 1985.
In a photoelectron microscope for carrying out the photoelectron emission microscopy, a high voltage of the order of several tens of kilovolts (KV) is applied between a specimen and an electrode mounted close to the specimen to create an electric field lens. This lens focuses a photoelectron image onto a fluorescent screen through image forming lenses. This image is created by the photoelectrons emitted from the specimen.
Since the two-dimensional distribution of the chemical composition and the chemical bonding energy of a specimen surface should be known as well as the structure or topography, both a transmission electron microscope and a photoelectron microscope have been required in the past. In this case, if the specimen is observed on one microscope, the specimen must be shifted from one microscope to the other. For this purpose, the specimen must be installed on the sample holder of the other microscope. In this way, quite laborious steps have been needed.
When a crystal of a specimen is grown and the specimen changes are observed, the observation is made while evaporating a substance onto the specimen. In the prior art transmission electron microscope, the substance is deposited on the surface of the specimen which faces the electron gun. Therefore, the evaporation source is located above the specimen. This makes it impossible to use a boat heater, crucible, or the like as the vapor source. Thus, the vapor source consists of a wire heater on which the metal to be vaporized is wound. With this type of vapor source, only a very small amount of metal can be evaporated in one operation. Consequently, it is difficult to observe the specimen while depositing a metal onto the specimen for an extended period of time. Another problem arises from the fact that the aforementioned wire heater is often made of a metal. Specifically, it is impossible to employ an evaporating substance which can easily combine with the material of the heater. Hence, great limitations are imposed on the evaporating substance.